1. Field of the Invention
This invention relates to bicycles, and more specifically to a dual wheel driven bicycle which uses an elongate flexible shaft or cable to provide rotational movement to the front wheel.
2. Description of the Prior Art
Inventors have been dreaming of a practical dual wheel driven bicycle for many years; unfortunately, none of these dreams have produced a practical dual wheel driven bicycle which can be easily and economically massed produced.
U.S. Pat. No. 4,029,332 which issued on Jun. 14, 1977 describes a rotacycle having a two-wheel drive system. The rotacycle discarded the chain and sprocket drive system of conventional bicycles and substituted an automatic variable-speed transmission which utilized a large rotor which was positioned between the front and rear tires. Rotational forces from the pedals were transferred from this transmission to the front and rear wheels by a system of belts, pulleys and opposing drive wheels which captured the opposing sidewalls of the tires. The rotacycle had an unusual appearance because it did not have a conventional chain and sprocket, and because of the large variable speed transmission which was positioned between the front and rear tires. The rotacycle has never achieved commercial success.
U.S. Pat. No. 4,479,660 which issued on Oct. 30, 1984, describes a two wheel synchronously driven bicycle. This synchronously driven bicycle utilizes a conventional power train to drive the rear wheel including pedals, cranks, a pedal sprocket, a continuous chain, and a rear sprocket. The front wheel is driven by a continuous belt. A drive pulley is connected to the conventional pedal sprocket and a front pulley is connected to the hub of the front wheel. The front pulley and the front wheel assembly includes a freewheeling hub. The continuous belt is stretched between the drive pulley on the pedal sprocket and the front pulley on the front wheel. Additional pulleys located near the handlebars guide the belt during rotation around the drive pulley on the pedal sprocket and the front pulley on the front wheel. Rotational forces from the pedals are transferred to the pedal sprocket which actuates both the continuous chain and the continuous belt providing torque to both the rear and front wheels respectively. This continuous belt requires constant tensioning and a special apparatus is provided for this purpose. The tensioning device and the continuous belt are relatively cumbersome, and may interfere with the operator's pedaling motion. This two wheel synchronously driven bicycle has never achieved commercial success.
The present invention relies upon an elongate flexible shaft or cable to transmit rotational forces to the front wheel, instead of the belts and pulleys utilized by the prior art.